Context: Piper nigrum Linn (Piperaceae) (PnL) is used in traditional medicine to treat gastric ailments, dyslipidemia, diabetes, and hypertension.
Objective: The present study explores the possible protective effects of P. nigrum extracts on high-fat diet-induced obesity in rats.
Materials and methods: High-fat diet-induced obese rats were treated orally with 200 mg/kg bw of different extracts (hexane, ethylacetate, ethanol, and aqueous extracts) of PnL for 42 d. The effects of PnL extracts on body composition, insulin resistance, biochemical parameters, leptin, adiponectin, lipid profile, liver marker enzymes, and antioxidants were studied.
Results and discussion: The HFD control group rats showed a substantial raise in body weight (472.8 ± 9.3 g), fat% (20.8 ± 0.6%), and fat-free mass (165.9 ± 2.4 g) when compared with normal control rats whose body weight, fat%, and fat-free mass were 314.3 ± 4.4 g, 6.4 ± 1.4%, and 133.8 ± 2.2 g, respectively. Oral administration of ethyl acetate or aqueous extracts of PnL markedly reduced the body weight, fat%, and fat-free mass of HFD-fed rats. In contrast to the normal control group, a profound increase in plasma glucose, insulin resistance, lipid profile, leptin, thiobarbituric acid reactive substance (TBARS), and the activities of lipase and liver marker enzymes, and a decrease in adiponectin and antioxidant enzymes were noted in HFD control rats. Administration of PnL extracts to HFD-induced obese rats significantly (p < 0.05) restored the above profiles.
Conclusion: PnL extracts significantly reduced the body weight, fat%, and ameliorated HFD-induced hyperlipidemia and its constituents.
Keywords: Antioxidants; fat%; hyperlipidemia; insulin resistance; obesity.